Declaring attribute namespace in xPath expression

my XML is:

    <?xml version="1.0" encoding="utf-16"?>
<LauncherInfo xmlns:xsi="http://ift.tt/ra1lAU" xmlns:xsd="http://ift.tt/tphNwY" xmlns="http://ift.tt/1vC7NUZ" hash="d8bf41f6053ab2df28704dfcda443f9199546d3b">
  <File Name="parakstitais.edoc" Location="vieta_kur_saglabat" />
  <Action xsi:type="CreateNewSignAction">
    <FileReferences>
        <FileReference Name="Document1.doc" Address=some url" />
        <FileReference Name="Scan7.pdf" Address="some url" />
        <FileReference Name="Scan8.pdf" Address=some url" />
    </FileReferences>
  </Action>
</LauncherInfo>

And idea is to receive all part, so i am compiling Xpath expression

xpath.compile("LauncherInfo/Action");

and an error appears: Namespace for prefix 'xsi' has not been declared. Is there any way to define namespace uri inside xPath expression?